Casing Fill and Circulation Tool with Metal Seal Featurel

ABSTRACT

A fill up and circulating tool has a threaded hub covered by a rapidly removable cover. The cover protects the threads from damage until a well kick occurs. When the well kicks the cover is rapidly removed and the fill up tool is brought down with the top drive to which it is connected. The top drive rotates the mandrel of the tool to make the threads up to a coupling on the uppermost stand of casing to provide a metal to metal seal that can resist a well kick coming up through the casing and around the outside of the fill up tool. The top drive system has a surface valve that can be closed quickly to contain the kick through the fill up tool.

FIELD OF THE INVENTION

The field of the invention is fill up and circulating tools for running casing and more particularly a metal seal feature on the tools allowing for rapid deployment against the casing in the event of a well kick.

BACKGROUND OF THE INVENTION

Casing fill and circulation tools are used to fill the casing as it is being built to run in the hole and then to circulate the string as it is lowered into the borehole. Circulation is typically carried out by having a self-actuating seal or an activated seal of a resilient material such as rubber contact the inner wall of the casing. Typically the seal of the fill up tool is kept outside the casing until there is a need to circulate and when that need arises the tool is lowered to get the seal inside the casing and against the casing inner wall. Various types of rubber seals have been used such as cup seals, inflatables or other constructions that are mechanically urged into contact with the inner casing wall. These designs serve well for holding back the pressures developed during circulation which are a function of the flow rate and the annulus size outside the casing as it is run into the hole. However, there is a possibility that the well may kick or blow out when casing is being run in. This kind of situation frequently requires a rapid response and the capacity to seal the inside of the casing against very high pressures. The resilient rubber seals of the past designs are not capable of holding such pressures. As a result what has been done in the past is that the fill up and circulating tool had to be pulled out of the casing after pumping heavy fluid through it to try to stabilize the well. However, in the interim period of pulling out the fill tool from the casing and threading on a valve, the well could actually blow again despite the pumping of heavy fluid. The present invention addresses this issue by allowing rapid deployment of a metal to metal seal without a need to pull out and lay down the fill up tool.

The following references represent the state of the art for fill up and circulating tool exterior seal arrangement designed to allow circulation as the casing is being run into the well: U.S. Pat. No. 5,584,343; EP0709543 A2; US 2013/0220610; WO 2012/021555 and U.S. Pat. No. 6,173,777. U.S. Pat. No. 5,439,061 is a casing hanger for a wellhead for placement between casing strings.

Those skilled in the art will better understand further aspects of the invention from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be found in the appended claims.

SUMMARY OF THE INVENTION

A fill up and circulating tool has a threaded hub covered by a rapidly removable cover. The cover protects the threads from damage until a well kick occurs. When the well kicks the cover is rapidly removed and the fill up tool is brought down with the top drive to which it is connected. The top drive rotates the mandrel of the tool to make the threads up to a coupling on the uppermost stand of casing to provide a metal to metal seal that can resist a well kick coming up through the casing and around the outside of the fill up tool. The top drive system has a surface valve that can be closed quickly to contain the kick through the fill up tool.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the normal operation of the fill up and circulating tool;

FIG. 2 is the view of FIG. 1 with the cover removed to expose threads;

FIG. 3 is the view of FIG. 2 with the tool lowered and the thread made up to the casing; and

FIG. 4 is an alternative embodiment schematically illustrating a metal bellows that folds in response mechanical or hydraulic actuation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1 the topmost stand of casing 3 has a threaded coupling 5. The fill up and circulation tool 1 of a known design is equipped with a threaded coupling assembly 4 that is shown in FIG. 1 with a removable cover 10 that is secured with quick release clamps. The cover 10 protects the male thread 6 of bushing 14 that is affixed to the mandrel 16 of the fill up and circulation tool 1. In normal operation the tool 1 is supported by a top drive 2 that is capable of raising and lowering the tool 1 as well as rotation of the tool 1.

In the event of a well kick with a pressure surge coming up the interior of the casing 3 the first response is to pump heavy fluid into the well to bring it toward stability and to buy time to lower the tool 1 to engage threads 6 with threads 5 to close off the casing 3 with a metal to metal seal in the form of an engaged thread. Note the positions of the bushing and coupling can be reversed but it is preferable to have the coupling on the top of the tubular string to protect its threads that are inside. The threading takes place with the assistance of the top drive that is schematically illustrated as 2. The exterior of the casing 3 can be sealed with blowout preventers that are not shown. IN a very short time without any need to remove the tool 1, the casing can be secured from a well kick with a metal to metal connection that can withstand the anticipated pressures from the kick.

FIG. 4 illustrates an alternative sealing arrangement that can be remotely actuated hydraulically with pressure in line 20 after the seal 22 is positioned in the casing 3. The hydraulic pressure can operate an actuating piston 24 that causes the metal seal 22 to move radially outwardly to contact the inner wall 26 of the casing 3. The metal seal 22 can be a bellows of adjacent surfaces that define at least one ridge so that the bellows collapses in one or more folds when axially compressed by piston 24 or another metal shape that can be urged to move radially to close an annular space between the tool 1 and the casing inner wall 26.

Those skilled in the art will appreciate that one advantage of the present invention is that it is mounted to the tool 1 when used in normal operation of running and circulating a casing string into a desired subterranean location. The ability to actuate a metal to metal seal in short order allows a response to occur in a very short time to a well kick which can reduce risk of injury to personnel as well as damage to rig equipment. No longer does the tool need to be disconnected and set down on a rig floor in the face of an emergency situation of a well kick or imminent blowout. The safety risks of handling the tool and needing to place it on a crowded rig floor under emergency conditions is also avoided, which again has the benefit of reducing personal injury or equipment damage. While the resilient seals in the past that were used to hold low pressures were somewhat of a barrier, in the case of blowout they lacked the pressure retaining capacity and operators were unwilling to depend on such seals for service beyond their intended purpose of holding back the pressure needed to overcome friction when circulating the casing string. While such resilient seals can still be employed as before for containing the pressure needed for circulation, the metal seal can be used in tandem to add new functionality in an emergency situation that has not been available before in a casing running situation.

The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below: 

We claim:
 1. A fill and circulation tool assembly for running a tubular string to a subterranean location, comprising: a mandrel having a passage therethrough and an end connection for support for selective placement in the tubular string; a metal seal mounted to said mandrel for selective actuation against an interior wall of the tubular string to retain a pressure surge from the subterranean location.
 2. The assembly of claim 1, further comprising: a resilient seal mounted to said mandrel for retention of pressure of fluid pumped through said passage when circulating fluid through said tubular string.
 3. The assembly of claim 1, wherein: said metal seal comprises a threaded bushing mounted to said mandrel.
 4. The assembly of claim 3, further comprising: a threaded coupling on the tubular string to accept said bushing.
 5. The assembly of claim 1, wherein: said metal seal comprises a threaded coupling mounted to said mandrel.
 6. The assembly of claim 5, further comprising: a threaded end on the tubular string to accept said coupling.
 7. The assembly of claim 1, wherein: said metal seal is axially compressed to extend radially into contact with an inner wall of the tubular string.
 8. The assembly of claim 7, wherein: said metal seal is mechanically or hydraulically actuated.
 9. The assembly of claim 7, wherein: said metal seal comprises a bellows.
 10. The assembly of claim 7, wherein: said metal seal comprises at least two surfaces defining at least one ridge that moves radially into contact with the tubular string.
 11. The assembly of claim 1, wherein: said metal seal further comprises a removable cover.
 12. The assembly of claim 11, wherein: said cover overlays an outer surface of said metal seal to protect said outer surface from damage during normal running and circulating the tubing string.
 13. The assembly of claim 11, wherein: removal of said cover allows said metal seal to enter the tubular string.
 14. The assembly of claim 1, wherein: said metal seal is actuated without mandrel removal from the tubular string.
 15. The assembly of claim 1, wherein: said mandrel is selectively moved axially and rotated by a top drive. 